The present invention relates to a fastening mechanism for removably fastening together two workpieces. The invention has particular application to a fastening mechanism for releasably securing a print head to a reciprocating carriage in a printer.
Dot matrix printers are becoming increasingly more important and useful in the field of high-speed document printing. Printers of this kind are extremely advantageous for use with data processing systems wherein it is required to provide a printout of the data generated at very high speeds.
In a wide variety of high-speed printers, a print head carriage carrying the dot matrix print head is slidably mounted on a support shaft and is movable in a bi-directional linear path back and forth along a printing line, the printing being performed by selectively operating a plurality of print wires or ink jets to produce a matrix of dots on a record medium to form alphanumeric characters thereon.
In a known matrix printer arrangement, as disclosed for example in U.S. Pat. No. 3,750,792, the print head unit is secured to the base of the carriage by a number of screws. However, this manner of securing the print head to the carriage has the disadvantage of rendering the removal of the print head for replacement or maintenance work time-consuming and rather difficult because of poor accessability and crowded space conditions around the matrix print head. For example, the screws may inadvertently be dropped into the printer housing while they are being removed or inserted, and they then must be found and retrieved from possibly even more inaccessible places in the printer. Also, the need to use a screwdriver to remove or tighten the screws may give rise to the risk of damaging intricate mechanical or electronic parts or components of the printer if the screwdriver is incorrectly or carelessly used.